What do you call a small solar cell?
I have a small solar system being 1.5KW and that takes up over 10 square meters of roof space, and only contributes to the power needs Not replaces the power.
As for making an inverter, I would not even consider it, and that is from a person who has done electronics for years and has been involved with alternate energy for a long time too and understand the facts.
As audioguru said there is too many functions to consider or you will have a useless piece of junk that will damage more equipment than it will power, and secondly the efficency of the inverter is very important or you will waste more power than you will convert.
Yes some of the Chinese made ones are cheaper than you can make it yourself, but one word of advice here......DONOT.... buy a "Power Jack" brand inverter as i know of over 10 people who had bought them and they ALL blew up within 2 months, and also have a couple on my workshop bench here awaiting repair (not worth repairing in my mind)
Pete.